Insulation system for covering a facade of a building

ABSTRACT

This invention relates to an improved insulation system for covering a facade of a building consisting of at least one insulation element, at least one mechanical fastener, which fastener fixes the insulation element to the facade of the building, whereby the insulation element has at least a first and a second layer, the first layer being directed to the facade having a bulk density being lower than the bulk density of the second layer, whereby at least one layer is made of mineral fibers, especially stone wool fibers and a binding agent and whereby the fastener has a shaft erecting through the insulation element into the building and a plug-plate being arranged on or in the outer surface of the insulation element. 
     To achieve an insulation system which has very good insulation characteristics, which can be produced for low costs and which can be fixed to the facade of a building without causing high labor costs the shaft if the fastener partly erects into the first layer of the insulation element in a direction parallel to the surface of the facade.

The invention relates to an adjustable insulation system for covering afacade of a building consisting of at least one insulation element andat least one mechanical fastener, which fastener fixes the insulationelement to the facade of the building, whereby the insulation elementhas at least a first and a second layer, preferably being connected toeach other, the first layer being directed to the facade having a bulkdensity being lower than the bulk density of the second layer and beinghighly flexible. The first layer therefore serves to provide acompensation layer to cope with irregularities often found whilecarrying out refurbishment and/or renovation measures. At least onelayer is made of mineral fibres, especially stone wool fibres and abinding agent, or of cellular plastic, especially expanded polystyrene(EPS). The fastener has a shaft erecting through the insulation elementinto the building substrate and a plug or a plug-plate being arranged onor flush with the outer surface of the insulation element. Saidinsulation systems also being known as External Thermal InsulationComposite Systems (ETICS).

Furthermore the invention relates to a method for installing aninsulation system covering a facade of a building with the steps offixing at least one insulation element having at least a first and asecond layer, preferably being connected to each other, whereby thefirst layer being directed to the facade has a bulk density being lowerthan the bulk density of the second layer and whereby at least one layeris made of mineral fibres, especially stone wool fibres and a bindingagent, using at least one mechanical fastener to fix the insulationelement to the facade of the building, whereby the fastener has a shafterecting through the insulation element into the building substrate anda plug or a plug-plate being arranged on or flush with the outer surfaceof the insulation element and fixing the fastener by increasing theouter diameter of the shaft protruding into the building substrate.

Finally the invention relates to a mechanical fastener for an insulationsystem for covering a facade of a building with a shaft having a lengthbeing longer than the thickness of the insulation element and a plug ora plug-plate being arranged at one end of the shaft.

Such insulation systems in general are well-known in the prior art. Inmodern roof and facade constructions it is common to employ mineralfibre insulating products comprising an insulation layer and a rigidsurface coating or layer on at least the one main surface of the productfacing the exterior of the insulated construction. Different insulationmaterials are known in the prior art as for example fibrous materialsmade of inorganic and/or organic fibres normally bound with a bindingagent.

For example DE 20 2009 001 532 U1 discloses a dual density facadeinsulation board having a soft inner layer which absorbs unevenness ofthe substrate and a hard outer layer forming the main layer and having abulk density between 180 and 280 kg/m³ on which a layer of render can bearranged. The soft inner layer has a bulk density between 30 and 80kg/m³. Both layers can be made from wood fibres or mineral fibres. Suchinsulation boards have several disadvantages. If these boards are madeof wood fibres they naturally have a very low fire resistance unlesshigh amounts of flame retardants are used. Moreover their thermalproperties are quite poor and the durability will be significantlyreduced when being exposed to moisture.

The fire resistance of such boards being made from mineral fibres ismuch better. Nevertheless, a layer of mineral fibres with a bulk densityof between 180 and 280 kg/m³ provides only low thermal resistance. Toachieve sufficient thermal resistances with these layers it is necessaryto use layers of great thickness. To use thick layers has thedisadvantage that the weight of such insulation boards is high so that alot of mechanical fasteners are necessary to fix these insulation boardsonto the facade or to use special fasteners which are able to carry abig load and which are therefore expensive and/or made of materials likemetal reducing the insulation properties of the insulation system. Touse insulation boards with high thicknesses together with a big amountof mechanical fasteners or special fasteners increases the price of suchinsulation systems namely the costs for the material and for the labour.The prior art uses mechanical fasteners being adjustable in view of thethickness of the insulation element only by reducing the distancebetween the plug-plate and the building in that the plug-plate is fixedto the shaft in a preferred distance thereby closing a hole in which ascrew is arranged.

Therefore, it is one object of the present invention to provide aninsulation system for covering a facade of a building at low totalinstalled costs, with good thermal insulating characteristics, which canbe fixed and adjusted to a building facade very easily without causinghigh labour costs.

Furthermore it is an object of the invention to provide a method forinstalling such an insulation system for covering a facade of a buildingwhich can easily and cheaply be provided onto a facade without usingexpensive components and which is particular useful for refurbishmentand/or renovation of facades wearing old substrates like e.g. loosemortar.

Finally it is an object of the invention to provide a mechanicalfastener for an insulation system for covering a facade of a buildingwhich can be installed easily in a wide range of applications and whichcan be used to level or adjust the outer layer of the insulationelement.

According to the invention this object is achieved with an insulationsystem for covering a facade of a building using an insulation elementcomprising a first layer which is highly flexible and a fastener havinga shaft providing a compensation zone which partly erects into saidfirst layer of the insulation element in a direction being mainlyparallel to a surface of the facade.

The first layer of the insulation element which is preferably made ofmineral fibres, especially stone wool fibres, and a binding agent has alow bulk density as from 30 kg/m³ to 70 kg/m³, especially as from 40kg/m³ to 60 kg/m³. Such a first layer has a high flexibility and isbendable so that such a first layer can compensate or equalize higherprotrusions in the surface of the facade, such as e.g. wires being fixedoutside of the building as it is known in connection with satelliteantennas etc.

Flexibility for the purpose of this invention, can be considered to becompression modulus of elasticity (according to European Standard EN826), wherein an increasing numerical value for the modulus ofelasticity indicates increasing stiffness respectively lowerflexibility. For simplification the first layer of the insulationelement respectively the element as such according to the invention maybe defined by the compressive stress at 10% strain to secure that acertain spring-back effect can be utilized during installation.

Furthermore, such a first layer can equalize a rough surface and/orirregularities because of substrates like more or less loose mortarbeing left on the facade surfaces during refurbishment or renovationmeasures. To compensate or equalize a rough surface means to level thesecond and/or each further layer, especially the outer layer of theinsulation element. A leveled outer layer of the insulation elementprovides a planar surface which is prepared to be covered with arendering system and which reduces the amount of rendering materialespecially in the areas of adjacent insulation elements.

According to the invention the shaft of the fastener partly erects intothe first layer of the insulation element in a direction parallel to asurface of the facade. Therefore the part of the shaft erecting into thefirst layer of the insulation element in a direction parallel to asurface of the facade additionally stabilizes the first layer of theinsulation element and increases the load bearing properties of theinsulation element. The part of the shaft erecting into the first layerof the insulation element in the direction parallel to the surface ofthe facade adds to the effect of a plate or a plug-plate fixing theinsulation element to the facade but in the level of the first layer ofa multilayered insulation element especially made of mineral fibres.Furthermore, the fastener can be easily used to level or adjust theouter surface of the insulation element.

The insulation system according to the invention reduces therefore theinstallation time because no further leveling step, like e.g. grinding,is needed to prepare a planar outer surface as the leveling can easilybe done by the first layer of the insulation system in combination withthe mechanical fasteners.

The insulation system is in particular useful in relation torefurbishment and/or renovation measures because old substrates likeloose mortar or rendering has not to be removed before fixing theinsulation element as the fasteners carry and stabilize the first layerof the insulation element by partly erecting into the first layer of theinsulation element in a direction parallel to a surface of the facade.In contrast to that prior art glued or partly glued ETICS require toremove loose mortar or rendering and surfaces need to be equalizedbefore insulation elements can be glued to. Thus such prior art systemsinvolve high labour and material cost.

Moreover, according to the invention small obstacles on the facade caneasily be covered due to the high flexibility of the first layer of theinsulation element. Therefore, no cutting of insulation elements isneeded to adapt the insulation elements to the facade.

Preferably a screw is provided in the shaft of the fastener with which afirst part of the shaft erecting into the building substrate is buckedup and with which a second part of the outer surface of the fastener isoriented from parallel to the outer surface of the fastener to mainlyperpendicular to the outer surface thereby protruding into the firstlayer of the insulation element. This screw has therefore the advantagethat it can be used to fix the fastener in the facade and the same timeto stabilize the first layer of the insulation element, while levelingthe outer surface of the insulation element by setting the length of theshaft of the fastener.

According to a preferred embodiment the second part of the shaft has atleast two areas protruding into the insulation element whereby the areasprotrude in at least two different directions, preferably perpendicularto each other into the insulation element. This further feature has theeffect that the stability of the first layer of the insulation elementis increased as the more areas protrude in different directions. It ispossible that the protruding areas protrude into only the first layer ofthe insulation element or into different, e. g. into the first and thesecond layer of the insulation element.

Preferably the insulation element has a third layer made of mineralfibres and a binding agent, which third layer has a bulk density beinghigher than the bulk density of the second layer and which third layerforming the outer layer has a high receptiveness and/or adhesion for therendering system. Such high receptiveness and/or adhesion for therendering system results in a high bond strength between the base coatof the rendering and the insulation element.

The insulation element being used in an insulation system according tothe invention has therefore three layers whereby the outer layer has incomparison to the two further layers the highest bulk density so thatthis third layer is very durable. The second layer which has incomparison to the third layer a reduced bulk density has good insulationcharacteristics and can be made with a bulk density achieving these goodinsulation characteristics. Finally the first layer being the layerwhich is in contact with the building has a low bulk density so thatthis layer can absorb unevenness of the surface of the buildingsubstrate. Therefore, the first layer being made highly flexible is ableto handle unevenness in the building surface of up to 15 to 20 mm,depending on the thickness of this layer.

According to a further feature of the invention the bond strengthbetween the third layer and the rendering layer amounts to between 0.010N/mm² and 0.080 N/mm², especially between 0.010 N/mm² and 0.030 N/mm²,preferably between 0.015 N/mm² and 0.025 N/mm², for example 0.020 N/mm².The insulation system according to the present invention having thebefore mentioned bond strength has moreover a high stability withoutusing a big number of mechanical fasteners even if the insulationelements are only fixed by these mechanical fasteners without gluing theinsulation onto the facade. This is achieved by using fastenersaccording to the invention and a three-layered insulation element havingspecial synchronized densities of the different layers which will bevery advantageous while fixing it to the facade. Said adjusted densitieson the one hand provide the needed rigidity and strength, e.g.pull-through strength for the mechanical fasteners in the third layerand on the other hand secure the good insulation characteristics of thesecond layer. Finally, the first layer which can be very slim inthickness compared to the other two layers and which of course has goodinsulation characteristics because of its low bulk density is able toequalize projections in the surface of the building facade. By choosingthe synchronized densities in accordance with the present invention theinsulation element even provides a controllable flexibility, i.e. a kindof spring-back effect which is very useful while leveling the surface ofthe ready installed insulation layer before applying the renderingsystem. Therefore, costly grinding of the insulation boards iscompletely avoided.

The bond strength between the layer of render, especially a base coatwhich is part of the layer of render respectively the rendering system,and the insulation element is measured in accordance with the Guidelinefor European Technical Approval ETAG No. 004 (e.g. edition March 2000),paragraph 5.1.4.1.1. The results are expressed in N/mm² (MPa).

Where appropriate, in order to increase the receptiveness and/oradhesion of the third or outer layer for the rendering system, theinsulation element on its outer surface may comprise a primer, coatingand/or an additive.

Preferably the third layer has a bulk density of 180 kg/m³ to 350 kg/m³,especially of 220 kg/m³ to 260 kg/m³. Furthermore, at least the thirdlayer is made of mineral fibres in an amount of 90 to 99 wt % of thetotal weight of starting materials in the form of a collected web and abinding agent in an amount of 1 to 10 wt % of the total weight ofstarting materials, whereby the collected web of mineral fibres issubjected to a disentanglement process, whereby the mineral fibres aresuspended in a primary air flow, whereby the mineral fibres are mixedwith the binding agent before, during or after the disentanglementprocess to form a mixture of mineral fibres and binding agent andwhereby the mixture of mineral fibres and binding agent is pressed andcured to provide a consolidated composite with a bulk density of 180kg/m³ to 350 kg/m³, especially of 220 kg/m³ to 260 kg/m³.

The percentages mentioned are based on dry weight of starting materials.As a result of the before mentioned production process a surprisinglyhomogenous layer of mineral fibres and a binding agent is achieved.Therefore the quality of the curing is significantly improved anduncured binder spots causing well known discoloration or so called brownspots on the rendering system are eliminated.

Such layers can be produced in a versatile and cost efficient method. Byadjusting the density to which the layer is pressed, a variety ofdifferent layers can be tailor-made for specific purposes. Therefore,these layers have a variety of uses, predominantly as building elements.In particular the layers can be in the form of panels. In general, thelayers are used in applications where mechanical stability and unevensurface finish as well as insulating properties are important. In someapplications the layers can be used as acoustically absorbing ceiling orwall panels. In other applications, the layers can be used as insulatingouter cladding for buildings. The precise quantity of mineral fibres ischosen so as to maintain appropriate fire resistance properties andappropriate thermal and/or acoustic insulation value and limiting cost,whilst maintaining an appropriate level of cohesion, depending on theappropriate application. A high quantity of fibres increases the fireresistance of the element, increases its acoustic and thermal insulationproperties and limits cost, but decreases the cohesion in the element.This means that the lower limit of 90 wt % results in an element havinggood cohesion and strength, and only adequate insulation properties andfire resistance, which may be advantageous for some composites, whereinsulation properties and fire resistance are less important. Ifinsulation properties and fire resistance are particularly important theamount of fibres can be increased to the upper limit of 99 wt %, butthis will result in only adequate cohesion properties. For a majority ofapplications a suitable composition will include a fibre amount of from90 to 97 wt % or from 91 to 95 wt %. Most usually, a suitable quantityof fibres will be from 92 to 94 wt %.

The amount of binder is also chosen on the basis of desired cohesion,strength and cost, plus properties such as reaction to fire and thermalinsulation value. The low limit of 1 wt % results in a layer with alower strength and cohesion, which is, however, adequate for someapplications and has the benefit of relatively low cost and potentialfor good thermal and acoustic insulation properties. In applicationswhere a high mechanical strength is needed, a higher amount of bindershould be used, such as up to the upper limit of 10 wt %, but this willincrease the cost for the resulting product and further the reaction tofire will often be less favorable, depending on the choice of binder.For a majority of applications, a suitable layer will include a binderamount from 3 to 10 wt % or from 5 to 9 wt %, most usually a suitablequantity of binder will be from 6 to 8 wt %.

The mineral fibres used for such a layer could be any mineral fibres,including glass fibres, ceramic fibres or stone fibres but preferablystone fibres are used. Stone wool fibres generally have a content ofiron oxide of at least 3% and alkaline earth metals (calcium oxide andmagnesium oxide) from 10 to 40%, along with the other usual oxideconstituents of mineral wool. These are silica; alumina; alkali-metals(sodium oxide and potassium oxide) which are usually present in lowamounts; and can also include titanium and other minor oxides. Fibrediameter is often in the range 3 to 20 microns, in particular 5 to 10microns, as conventional.

An alternative third layer used in an insulation system according to thepresent invention is made of mineral fibres in an amount of from 24 to80 wt % of the total weight of starting materials in the form of acollected web, an aerogel particulate material in an amount of from 10to 75 wt % of the total weight of the starting materials and a bindingagent in an amount of from 1 to 30 wt % to the total weight of startingmaterials, whereby the mineral fibres are suspended in the primary airflow, whereby the aerogel particulate material is suspended in theprimary air flow, whereby mixing the aerogel particulate with thesuspended mineral fibres, whereby the mineral fibres are mixed with thebinding agent before, during or after the mixing of the aerogelparticulate material with the mineral fibres to form a mixture ofmineral fibres, aerogel particulate material and binding agent andwhereby the mixture of mineral fibres, aerogel particulate material andbinding agent is pressed and cured to provide a consolidated compositewith a bulk density of 180 kg/m³ to 350 kg/m³, especially of 220 kg/m³to 260 kg/m³.

Preferably, the binding agent of the third layer is a dry binder,especially a powdery binder, e.g. phenol formaldehyde binder, phenolurea formaldehyde binder, melamine formaldehyde binder, condensationresins, acrylates and/or other latex compositions, epoxy polymers,sodium silicate, hotmelts of polyurethane, polyethylene, polypropyleneand/or polytetrafluorethylene polymers. The use of a dry binder,preferably a phenol formaldehyde binder, as this type of binder iseasily available and has proved efficient, has the advantage that mixingis easy and furthermore the need for maintenance of the equipment islow. Finally such binder is relatively stable and storable.

The percentages mentioned are based on dry weight of starting materials.

Such a layer can be manufactured in a very versatile and cost efficientway. A wide range of properties in terms of e.g. mechanical strength,thermal insulation capability etc. can be produced by altering thequantity of each component. This means that a variety of differentlayers can be made that are tailor-made for specific purposes.

Mixing the fibres and the aerogel particulate material as a suspensionin an air flow provides a surprisingly homogeneous composite, especiallyconsidering the considerable differences in the aerodynamic propertiesof these materials. This high level of homogeneity in the layer resultsgenerally in an increased level of mechanical strength relative to thelayers of the prior art for a given combination of quantities of thelayers. The increased homogeneity of the layer also has other advantagessuch as aesthetic appeal and consistency of properties throughout asingle layer. As a result of mixing the aerogel particulate materialwith the mineral fibres when suspended in an air flow the aerogelparticulate material is allowed to penetrate into the tufts of fibresthat are present. In contrast, when the mixing process involves physicalcontact of, for example a stirrer with the fibres, the fibres tend toform compact balls, which the aerogel particulate material cannotpenetrate easily. The result of this can be that, in cases where themixing process involves physical contact, the final product containsareas where the aerogel and the fibres are visibly separated in distinctzones.

The layers have a variety of uses as it is described above standing.

Aerogel when used in the broader sense means a gel with air as thedispersion medium. Within that broad description, however three types ofaerogel exist which are classified according to the conditions underwhich they have been dried. These materials are known to have excellentinsulating properties owing to their very high surface areas, and highporosity. They are manufactured by gelling a flowable sole gel-solutionand then removing the liquid from the gel in a manner that does notdestroy the pores of the gel.

Preferably the second layer of the insulation element has a bulk densityas from 40 kg/m³ to 120 kg/m³, especially of 80 kg/m³. Such second layerbeing preferably made of mineral fibres, especially stone wool fibreshas excellent insulation characteristics. Therefore, to achieve goodinsulation characteristics of the building the thickness of such layercan nowadays be in a range of up to 100 mm. However, even fulfillingfuture requirements with higher thicknesses the total weight of aninsulation element using such a second layer is so low that theinsulation element can be fixed without gluing but only with mechanicalfasteners.

The fastener according to the invention has a screw-like shaft and aplug and/or a plug-plate which plug and/or plug-plate is preferablyarranged in the outer layer of the insulation element in that the plugand/or plug-plate is flush with the outer surface of the outer layer ofthe insulation element. For this purpose the outer layer of theinsulation needs the before mentioned bulk density so that the plugand/or plug-plate can be arranged flush with the outer surface of theouter layer. This arrangement has the big advantage that the renderingsystem can be provided with a low thickness because the plug and/orplug-plate has not to be embedded into the layer of render, i.e. thebase coat and no pre-priming of the plug-plate is required.

Preferably the insulation element is fixed to the facade by a low numberof mechanical fasteners, e. g. by one fastener per square meter of theinsulation element. To reduce the specific number of the mechanicalfasteners has the advantage that the cost for the material and the costfor the labour used to build up such an insulation system are decreased.

The rendering system is normally a multi-layer coat system containing atleast a base coat and a finishing coat. Moreover, a reinforcement meshmay be embedded in the base coat.

The before described insulation system provides in comparison to theprior art a faster installation time, an improved reliability byreduction of defects and errors, good insulation characteristics andthus an enhanced comfort and improved indoor climate. Moreover, a lowersystem price and a shorter site time are achieved.

According to the invention this object is achieved with a methodaccording to the independent method claim with the step of erecting apart of the shaft of the fastener into the first layer of the insulationelement in a direction parallel to a surface of the facade.

The advantages of this method are described before with respect to theinsulation system according to the invention. The method according tothe invention can preferably be used for refurbishment and/or renovationof existing buildings having no heat and/or sound insulation or a heatand/or sound insulation which is not up to date and needs to beimproved.

According to the method the insulation element is fixed to the facade bya fastener having a shaft with a first part erecting into a bore hole inthe building substrate and which is bucked up by a screw provided in theshaft so that the shaft is interlocked in the bore hole. Afterinterlocking the shaft in the bore hole a second part of the outersurface of the fastener is oriented from an orientation parallel to theouter surface of the fastener to an orientation mainly perpendicular tothe outer surface of the fastener by turning the screw in the shaft ofthe fastener so that the original length of the fastener is reduced.Reducing the length of the fastener has the result that the second partof the fastener protrudes into the first layer of the insulationelement. Before the length of the fastener is reduced but after thefastener is interlocked in the bore hole the plug or the plug-plate isarranged on top of or with a small distance to the outer surface of theinsulation element. Reducing now the length of the shaft of the fastenerresults in an embedding of the plug or plug-plate in the outer layer ofthe insulation element so that the outer surface of the plug or theplug-plate is arranged flush with the outer surface of the outer layerof the insulation element.

To simplify the arrangement of the plug or plug-plate flush with outersurface of the outer layer of the insulation element the plug or theplug-plate has knife like means to cut material of the outer surface ofthe outer layer of the insulation element, which are arranged on asurface of the plug or the plug-plate oriented to the outer surface ofthe outer layer of the insulation element. Furthermore, this surface ofthe plug or the plug-plate is provided with several recesses to collectmaterial being cut from the surface of the outer layer of the insulationelement while moving the plug or plug-plate into the outer layer of theinsulation element. To remove material from the outer surface of theouter layer of the insulation element has the advantage that outerlayers with higher bulk densities van be used. Such layers simplify theestablishment of an insulation system according to the invention havinga planar outer surface on which a thin rendering system can fixed easilythereby reducing the required rendering material and the weight of therendering system as well as the whole insulation system, which weighthas to be carried more or less by the fasteners.

According to a further feature of the method according to the inventionat least two areas of the second part of the shaft are protruding intothe insulation element in at least two different directions, preferablyperpendicular to each other. The fixing and stabilizing properties ofthe insulation system are enhanced by this feature.

In accordance with the insulation system and/or the method according tothe invention fasteners are used having a shaft with a length beinglonger than the thickness of the insulation element and a plug or aplug-plate being arranged at one end of the shaft. According to theinvention the shaft of the fastener is divided into at least a firstpart and a second part, which second part having a certain diameter isprovided with means which erect outwardly of the diameter by decreasingthe length of the shaft via an internal pulling element. Such means areformed by e.g. providing the second part of the shaft with a slit andadditionally an area of increased width, preferably in circular shape.Said slit having a length of about 20 to 35 mm ensuring that the meanswhen erected outwardly provide a kind of spring which supported by theflexibility of the insulation element creates a preload on themechanical fastener, i.e. the plug-plate, thereby providing a controlmechanism for the mounting and setting of the fastener. The preload onthe fastener may be in a range of between 100 to 600 N per fastener.

According to a further feature of the fastener these means erectingoutwardly are parts of the shaft which is interrupted by two slits beingarranged on radially opposite sides of the shaft, whereby each slit hasan area of increased width, preferably in circular shape.

Finally, the second part of the shaft has at least two areas erectingoutwardly of the diameter in at least two different directions,preferably perpendicular to each other by decreasing the length of theshaft via the internal pulling element. The internal pulling element ispreferably a screw being arranged in the shaft and being connected tothe first part of the shaft which is used to fix the shaft in a hole ofa building facade.

The invention will be described in the following by way of example andwith reference to the drawings in which

FIG. 1 is a schematic drawing of an insulation element being part of aninsulation system for covering a facade of a building;

FIG. 2 is an enlarged drawing of a part of the insulation systemaccording to circle I in FIG. 1;

FIG. 3 is an enlarged drawing of a part of the insulation systemaccording to circle II in FIG. 1;

FIG. 4 is an enlarged drawing of a part of the insulation systemaccording to circle III in FIG. 1;

FIG. 5 is an enlarged drawing of a part of the insulation systemaccording to circle IV in FIG. 1;

FIG. 6 is a side view of a fastener partly as sectional view;

FIG. 7 is a schematic drawing of an insulation element fixed to a facadeof a building with a fastener in a first position;

FIG. 8 is a schematic drawing of the insulation element fixed to thefacade of the building with the fastener in a second position and

FIG. 9 is a schematic drawing of the insulation element fixed to thefacade of the building with the fastener in a third position.

FIG. 1 shows a part of an insulation system 1 for covering a facade 2 ofa building. The insulation system consists of several insulationelements 3 of which only one insulation element 3 is shown in FIG. 1.The insulation element 3 is fixed with only mechanical fasteners 4 tothe facade 2. These mechanical fasteners 4 will be described later.

Furthermore, the insulation system consists of a rendering system 5being shown only partly in FIG. 1 and consisting of a base coat 6 and afinishing coat 7. The rendering system 5 is based on mortar and can bemodified with an adhesive resin.

The insulation element 3 consists of a first layer 8, a second layer 9being arranged on the first layer 8 and a third layer 10 being arrangedon the second layer 9. Said at least second and third layer 9, 10 may beproduced as an integral element, so called dual-density product, in atraditional manner whereafter the first layer 8 is glued to saidelement. However, various alternatives are conceivable and within thescope of the invention.

The third layer 10 is made of mineral fibres and a binding agent and hasa bulk density being higher than the bulk density of the second layer 9which is made of mineral fibres and a binding agent. The bulk density ofthe third layer 10 is 240 kg/m³. This third layer 10 has a thickness ofapproximately 30 mm. The third layer 10 is fixed to the second layer 9for example by gluing.

The second layer 9 which is made of stone wool fibres and a bindingagent has a bulk density of approximately 80 kg/m³ so that this secondlayer 9 has good insulation characteristics, especially a good totalthermal resistance.

The mineral fibres of the second layer 9 can be arranged parallel to thesurfaces of the insulation element 3 which are substantially orientedparallel to the facade 2. For certain uses it may be of advantage toarrange the mineral fibres of the second layer 9 perpendicular to thesesurfaces. The advantage of the arrangement of the mineral fibresperpendicular to these surfaces is that the insulation element 3 hasincreased compression strength in comparison to an insulation element 3having a second layer 9 with an orientation of the mineral fibresparallel to these surfaces.

Nevertheless a second layer 9 of an insulation element 3 with a fibreorientation substantially parallel to these surfaces has improvedthermal insulation characteristics in comparison to an insulationelement 3 with a second layer 9 having a fibre orientation perpendicularto the surfaces.

The first layer 8 which is made of mineral fibres and a binding agentand which is fixed to the second layer 9 and which is in contact withthe facade 2 has a bulk density of approximately 50 kg/m³ so that thisfirst layer 8 has a high flexibility and is highly compressible. Thethickness of said layer preferably amounts to about 30 to 40 mm so thatirregularities of the building facade, like e.g. offsets, protrusions,cables etc., can be equalized. The fibre orientation is chosen as tosecure that a compression stress at 10% strain (EN 826) of theinsulation element 3 of at least 5 kPa is achieved. Because of thecharacteristics of the third layer 10, especially the high bulk densitythe bond strength between the third layer 10 and the rendering system 5is 0.020 N/mm². To achieve this bond strength the third layer 10 is madeaccording to a further alternative of mineral fibres in an amount ofaround 96 wt % of the total weight of starting material in the form of acollected web and a binding agent in an amount of 4 wt % of the totalweight of starting materials, whereby the collected web of mineralfibres is subjected to a disentanglement process, whereby the mineralfibres are suspended in a primary air flow, whereby the mineral fibresare mixed with a binding agent before the disentanglement process toform a mixture of mineral fibres and binding agent and whereby themixture of mineral fibres and binding agent is pressed and cured toprovide a consolidated composite with a bulk density of 240 kg/m³.

According to yet another alternative the third layer 10 is made ofmineral fibres in an amount of about 70 wt % of the total weight ofstarting materials in the form of a collected web, an aerogelparticulate material in an amount of 25 wt % of the total weight ofstarting materials and a binding agent in an amount of 5 wt % of thetotal weight of starting materials, whereby the mineral fibres aresuspended in a primary air flow, whereby the aerogel particulatematerial is suspended in the primary air flow, thereby mixing theaerogel particulate material with the suspended mineral fibres, wherebythe mineral fibres are mixed with the binding agent before mixing of theaerogel particulate material with the mineral fibres to form a mixtureof mineral fibres, aerogel particulate material and binding agent andwhereby the mixture of mineral fibres, aerogel particulate material andbinding agent is pressed and cured to provide a consolidated compositewith a bulk density of 240 kg/m³.

Because of the low bulk density the first layer 8 of the insulationelement 3 has characteristics which allow to equalize and compensate forunevenness of the facade 2 as can be seen in FIGS. 2 to 4 by examples.FIG. 2 shows a protrusion 13 of the facade, like e.g. a concrete ridge,which is equalized by the first layer 8 in that the first layer 8 iscompressed in the area of the protrusion 13.

FIG. 3 shows an offset 14 of the facade 2 which is equalized by thefirst layer 8 of the insulation element 3 in that the first layer 8 iscompressed in the area of the part of the offset 14 erecting to theinsulation element 3.

FIG. 4 shows a cable 15 fixed on the facade 2 and being covered by theinsulation element 3. As can be seen from FIG. 4 the first layer 8 ofthe insulation element 3 is compressed in the area of the cable 15.

The mechanical fastener 4 shown especially in FIGS. 6 to 9 has ascrew-like shaft 11 and a plug-plate 12 being arranged at one end of theshaft 11. The plug-plate 12 is arranged in the third layer 10 of theinsulation element 3 in that the plug-plate 12 is flush with the outersurface of the third layer 10 of the insulation element 3. FIG. 5 showsthe mechanical fastener 4 with the shaft 11 and the plug-plate 12 beingarranged flush with the outer surface of the third layer 10.

The screw-like shaft 11 of the fastener 4 has a bore 16 running in axialdirection through the shaft 11 and being open at both ends of the shaft11. The bore 16 has different diameters whereby the diameters decreasefrom the end of the shaft 11 being connected to the plug-plate 12 to theopposite end 17 where an external screw thread 18 is arranged at theouter surface of the shaft 11. The end 17 is split in two fingerlikeparts 19 which can be bulked or spread up via a screw 20 being insertedinto the bore 16 and having a screw head 21 with a diameter bigger thanthe diameter of the bore 16 below the screw head 21 so that the bore 16has a shoulder 22 on which the screw head 21 rests.

Furthermore the shaft 11 has two outer shoulders 23, 24, which are usedfor a contact at the shaft 11 on the facade 2 and on the outer surfaceof the first layer 8, so that a movement of the shaft 11 in axialdirection is limited by the shoulders 23, 24.

The shaft 11 has a length being longer than the thickness of theinsulation element 3. The shaft 11 is divided into a first part 25 and asecond part 26 which second part 26 has a diameter being provided withmeans 27 which erect outwardly of the diameter by decreasing the lengthof the shaft 11 via the screw 20 which is an internal pulling element.

The first part 25 of the shaft 11 is used to fix the shaft 11 in a hole28 (FIGS. 7 to 9) in the facade 2. The means 27 erecting outwardly areparts of the shaft 11 in the area of the second part 26. These means 27are arranged between two slits 29 interrupting the shaft 11 and beingarranged on radially opposite sides of the shaft 11. Each slit 29 has anarea 30 of increased diameter with a circular shape. From FIG. 6 it canbe seen that the second part 26 of the shaft 11 has two areas beingerectable outwardly in at least two different directions of the shaft11, namely perpendicular to each other, by decreasing the length of theshaft 11 via the screw 20.

The shaft 11 is connected to the plug-plate 12 which is arranged at oneend of the shaft 11. The plug-plate 12 has an opening 31 which allowsthe insertion of a tool to turn the screw 20 having an external screwthread 32 being arranged at the end opposite of the screw head 21 andbetween the fingerlike parts 19.

The plug-plate 12 has knifelike means 33 which are arranged on the outersurface of the plug-plate 12 being oriented to the shaft 11 and whichare combined with recesses 34 in which material being cut from thesurface of the outer layer 10 by the knifelike means is collected.

FIGS. 7 to 9 show the fastener 4 in different positions during mountingand fixing of an insulation element 3 on a facade 2. Just for reasons ofsimplification the insulation element 3 is shown with only two layers 8and 9 and the rendering system 5 in FIG. 9.

FIG. 7 shows a first position in which the insulation element 3 isarranged on top of facade 2. After a hole has been drilled through theinsulation element 3 into the building substrate the fastener 4 isinserted with his end opposite of the plug-plate 12 into the hole 28.The plug-plate 12 is lying on top of the surface 35 of the second layer9. In this position the screw 20 is screwed so that the external screwthread 32 pulls the fingerlike parts 19 of the shaft 11 towards theplug-plate 12 thereby spreading the fingerlike parts 19 in a way thatthe shaft 11 is clamped within the hole 28 to withstand drag forces inthe direction of the longitudinal axis of the shaft 11. This positionwith the spread up fingerlike parts 19 is shown in FIG. 8. By spreadingup the fingerlike parts 19 the overall length of the shaft 11 isslightly shortened.

Starting in FIG. 8 the screw 20 is turned furthermore so that the means27 in the second part 26 of the shaft 11 are directed into the firstlayer 8 so that these means 27 form clamp like fingers fixing the firstlayer 8 to the facade 2. By this the length of the shaft 11 will befurther shortened and spring-back forces resulting from the highlyflexible first layer 8 will be utilized. To utilize said forces andcontrol the mounting and setting of the fastener in a practical mannerthe length of the shaft 11 in a first step often will be reduced byaround 5 to max. 15 mm depending on the conditions on site. Saidreduction of the insulation thickness is therefore to be consideredwhile planning and designing the insulation system 1 according to theinvention. During this step of the method the plug-plate 12 can beturned without the shaft 11 to cut with the knifelike means 33 into theouter surface 35 of the second layer 9 so that the plug-plate 12 finallyis embedded into the second layer 9 with the plug-plate 12 beingarranged flush with the outer surface 35 of the second layer 9. Afterthat the rendering system 5 can be applied to the outer surface 35 ofthe second layer 9.

In an embodiment with a fastener which plug-plate 12 and shaft is onepiece the before described method is different in that in first stepafter the fastener is inserted with the shaft into the hole 28 is turnedso that the knifelike means 33 of the plug-plate 12 remove material fromthe surface 35 of the outer layer 9 until the plug-plate 12 is arrangedflush with the outer surface 35 of the layer 9. After that the screw 20is screwed until the fingerlike parts 19 are spread up and the shaft 11is fixed in the hole 28. Turning the screw has than the effect that themeans 27 in the second part 26 of the shaft 11 are moved from anorientation parallel to the outer surface of the fastener 4 to anorientation mainly perpendicular to the outer surface thereby protrudinginto the first layer 8 of the insulation element 3. This embodiment hasthe advantage that the mounting and setting of the fastener 4 is bettercontrollable as a certain preload on the fastener is immediatelytangible for the professional installer.

Due to its adjusting properties resulting from the spring-back effect ofthe combined effect of the first layer 8 and the second part 26 of thefastener 4 the insulation system 1 according to the invention isparticularly useful for refurbishment and/or renovation of facadeswearing old substrates like e.g. loose mortar. Moreover, such system 1can easily and cheaply be provided onto a facade without using expensivecomponents.

REFERENCE LIST

-   1 insulation system-   2 facade-   3 insulation element-   4 mechanical fastener-   5 rendering system-   6 base coat-   7 finishing coat-   8 first layer-   9 second layer-   10 third layer-   11 shaft-   12 plug-plate-   13 protrusion-   14 offset-   15 cable-   16 bore-   17 end-   18 external screw thread-   19 fingerlike parts-   20 screw-   21 screw head-   22 shoulder-   23 outer shoulder-   24 outer shoulder-   25 first part-   26 second part-   27 means-   28 hole-   29 slit-   30 area-   31 opening-   32 external screw thread-   33 knifelike means-   34 recess-   35 surface

1. An insulation system for covering a facade of a building consistingof at least one insulation element and at least one mechanical fastener,which fastener fixes the insulation element to the facade of thebuilding, whereby said insulation element has at least a first and asecond layer, preferably being connected to each other; said first layerbeing directed to the facade having a bulk density being lower than thebulk density of the second layer; at least one layer is made of mineralfibers, especially stone wool fibers and a binding agent, or of cellularplastic, especially expanded polystyrene (EPS), said fastener has ashaft erecting through the insulation element into the building and aplug or a plug-plate being arranged on or flush with the outer surfaceof the insulation element, characterized in that said shaft of thefastener partly erects into the first layer of the insulation element ina direction parallel to a surface of the facade.
 2. The insulationsystem according to claim 1, characterized in that a screw is providedin the shaft of the fastener with which a first part of the shafterecting into the building is bucked up and with which a second part ofthe outer surface of the fastener is oriented from parallel to the outersurface of the fastener to mainly perpendicular to the outer surfacethereby protruding into the first layer of the insulation element. 3.The insulation system according to claim 2, characterized in that thesecond part of the shaft has at least two areas protruding into theinsulation element whereby the areas protrude in at least two differentdirections, preferably perpendicular to each other into the insulationelement.
 4. The insulation system according to claim 1, characterized inthat a third layer is being arranged on the second layer and which thirdlayer has a bulk density of 180 kg/m³ to 350 kg/m³, preferably of 220kg/m³ to 260 kg/m′, especially of 240 kg/m³.
 5. The insulation systemaccording to claim 1, characterized in that the element as such isdefined by a compressive stress at 10% strain to secure that a certainspring-back effect can be utilized during installation.
 6. Theinsulation system according to claim 1, characterized in that the firstlayer has a compressive strength of 5 kPa to 15 kPa, preferably of 5 kPato 10 kPa and/or in that a preload on the fastener is in a range ofbetween 100 N to 600 N per fastener.
 7. The insulation system accordingto claim 1, wherein the first layer of the insulation element has a bulkdensity of from 30 kg/m³ to 70 kg/m³, preferably 40 kg/m³ to 60 kg/m³,especially of 50 kg/m³.
 8. The insulation system according to claim 1,wherein the second layer (9) of the insulation element has a bulkdensity as from 40 kg/m³ to 120 kg/m³, preferably 60 kg/m³ to 90 kg/m³,especially of 80 kg/m³.
 9. The insulation system according to claim 1,wherein the plug and/or a plug-plate of the mechanical fastener isarranged in the third layer of the insulation element in that the plugand/or plug-plate is flush with the outer surface of the third layer ofthe insulation element.
 10. The insulation system according to claim 1,wherein the insulation element is fixed to the facade by at least onemechanical fastener per square meter of the insulation element.
 11. Theinsulation system according to claim 1, whereby the second layer hasfibers being substantially oriented parallel to the surfaces of thesecond layer.
 12. The insulation system according to claim 1, wherebythe second part of the shaft for each area protruding into theinsulation element has a length of approximately 5 to 40 mm, preferably25 to 30 mm.
 13. A method for installing an insulation system forcovering a facade of a building according to claim 1 with the followingsteps: fixing at least one insulation element having at least a firstand a second layer, preferably being connected to each other, wherebythe first layer being directed to the facade has a bulk density beinglower than the bulk density of the second layer and whereby at least onelayer is made of mineral fibers, especially stone wool fibers and abinding agent, using at least one mechanical fastener to fix theinsulation element to the facade of the building, whereby the fastenerhas a shaft erecting through the insulation element into the buildingsubstrate and a plug and/or a plug-plate being arranged on or flush withthe outer surface of the insulation element, fixing the fastener in thebuilding by increasing the outer diameter of the shaft protruding intothe building substrate and erecting a part of the shaft of the fastenerinto the first layer of the insulation element in a direction parallelto a surface of the facade.
 14. The method according to claim 13,whereby the fastener with a first part of the shaft erecting into thebuilding substrate is bucked up by a screw provided in the shaft withwhich a second part of the outer surface of the fastener is moved froman orientation parallel to the outer surface of the fastener to anorientation mainly perpendicular to the outer surface thereby protrudinginto the first layer of the insulation element.
 15. The method accordingto claim 13, whereby at least two areas of the second part of the shaftare protruding into the insulation element in at least two differentdirections, preferably perpendicular to each other.
 16. A fastener foran insulation system for covering a facade of a building according toclaim 1, with a shaft having a length being longer than the thickness ofthe insulation element and a plug and/or a plug-plate being arranged onone end of the shaft, characterized in that the shaft is divided into atleast a first part and a second part, which second part having adiameter is provided with means which erect outwardly of the diameter bydecreasing the length of the shaft via an internal pulling element. 17.The fastener according to claim 16, whereby the internal pulling elementis a screw being arranged in the shaft and being connected to the firstpart of the shaft which is used to fix the shaft in a hole of a buildingfacade.
 18. The fastener according to claim 16, whereby the meanserecting outwardly are parts of the shaft which is interrupted by twoslits being arranged on radially opposite sides of the shaft, wherebyeach slit has an area of increased width, preferably in circular shape.19. The fastener according to claim 16, whereby the second part of theshaft has at least two areas being erectable outwardly in at least twodifferent directions of the shaft, preferably perpendicular to eachother, by decreasing the length of the shaft via an internal pullingelement.